This invention relates in general to systems for removing contaminants from liquids and, more specifically to a system for removing toxic chemicals and volatile gases (such as methyl tertiary butyl ether [MTBE], benzene, trihalomethanes, and the like), volatile chemical contaminants, pesticides, particles such as algae, other suspended organic and inorganic solids, chemicals, dissolved oils, and other particles including large and heavy particles and light, fine, or buoyant particles from water.
This present invention relates to an improvement in a pretreatment filtration system which removes most contaminants from raw influent water before the water to be processed enters the treatment plant filtration system.
Proper water treatment and filtration are major concerns for the health and safety of all inhabitants where ever located. Improper treatment and/or disposal causes health problems, disease, and even death. The Center for Disease Control (CDC), through DNA tests, identified human sewage as the source of the 1993 Milwaukee, Wis., Cryptosporidium parvum parasite outbreak that infected over 400,000 people in that city. In the latest issue of the CDC""s, Emerging Infectious Diseases Journal, the results are reported on the molecular analysis of 39 isolates of Cryptosporidium parvum from human and bovine sources in nine human outbreaks, including isolates from the 1993 Milwaukee outbreak. The new study suggests that the source of the parasite Cryptosporidium parvum in the Milwaukee outbreak is human, not bovine.
Four stool specimens were examined from the Milwaukee outbreak: three from the original outbreak and a fourth from an AIDS patient in 1996 who had initially been infected in the 1993 outbreak. All four were found only in isolates from humans. None of the four isolates were capable of producing an infection in laboratory animals.
Animal waste was also identified by DNA tests as the source of the Canadian E. coli outbreak that infected over 2,000 people in Walkerton, Ontario, following a summer rainstorm in May 2000. A deadly strain of E. coli bacteria was distributed by the Walkerton, Ontario public water supply in May, killing six people and infecting 2,000 others. New Canadian regulations were passed forcing municipalities to ensure the water is safe and to thereby prevent any recurrence.
Canadian municipalities must release their first public water quality reports by Oct. 30, 2000. Municipalities that violate the rules face fines ranging from $20,000 to $2 million. Jail sentences can also be imposed. This new regulation establishes tougher drinking water standards and policies that reflect the most current expertise and procedures in drinking water protection. Additionally, the U.S. Consumer Confidence Report requires every public water utility to distribute a detailed analysis of the chemicals, parasites, bacteria and virus in their public water supply for the previous year to all homeowners. These water quality reports are increasing the demand for better technology that works.
All public water districts using surface water must install filtration equipment and hire a State certified grade-3 plant operator by the year 2003, which is the Clean Water Act regulations deadline for small water districts. The largest immediate market for pre-filtration systems are in those states with the highest number of small water districts using surface water. Efficient and effective pre-filtration systems are a mandated necessity under current regulations/requirements. The pre-filtration system of the present invention meets, and exceeds, the challenges imposed by these regulations/requirements and far surpasses current pre-filtration systems in that challenge.
Water supplies for domestic drinking water, process water for chemical plants, or other liquids are often contaminated with a variety of contaminants, such as, but not limited to, toxic chemicals, volatile chemical contaminants (such as MTBE, benzene, perchlorate, trihalomethanes, and the like), pesticides, particles such as algae, other suspended organic and inorganic solids, dissolved oils, and other particles including large and heavy particles and light, fine, or buoyant particles (referred to collectively as contaminants). These contaminants must be removed in a reliable and cost-effective, cost-efficient manner.
The pre-filtration water decontamination system of the present invention was designed to remove most of the organic suspended solids (such as, but not limited to, algae), and volatile toxic chemicals from the raw influent water before it enters a final-stage treatment plant filtration system. Pre-filtration is necessary for a more efficient operation of the final-stage filtration. Common pre-filtration systems include use of sand filters, membrane filters, chemical flocculation-sedimentation-filtration (settle-to-the-bottom method), and large tank-type dissolved air flotation (DAF) systems. These systems and methods do work at pre-filtration but are not as effective nor as efficient as is necessary for proper pre-filtration.
Many older water treatment plants use gravitational separation methods, typically in sedimentation systems or dual-media sand filtration systems that may not be acceptable under the newer water quality standards. In some cases, these systems can meet the standards through the use of properly mixed polymer chemical filter aids. The required expensive and complex polymer chemical mixing equipment requires constant attention, since the amount of the chemicals being added to raw water must be frequently readjusted to match the continually changing chemistry of the water being filtered. Slow sand filters require a considerable investment, but generally can be operate for longer periods without cleaning. Unfortunately, even with pretreatment, both dual-media and slow sand filters fail to meet water quality standards for hours or several days after each backwash cleaning. Ordinary sand filters become overwhelmed after every rainstorm. Membrane filters, which generally are more efficient than sand filters, quickly clog and require constant attention whenever it rains. The system of the present invention actually becomes more efficient when turbidity increases.
Ordinary chemical flocculation and sedimentation processes are slow, require chemicals, and their maintenance is high. Moreover, they do not prevent toxic chemicals, pesticides and algae from passing through the ordinary filter bed. If algae spores, for example, are present when chlorine is added, toxic disinfection byproducts are formed, which is highly undesirable and a violation of the USEPA Safe Drinking Water Act. The inability of older municipal filtrations systems to remove algae is apparent in the lack of clarity found when a swimming pool is filled with xe2x80x9ccleanxe2x80x9d tap water. Most pool contractors have to shock tap water with large doses of chlorine chemical pool oxidizer to achieve the desired clear pool water appearance.
Some decontaminating systems, such as air stripping towers, currently discharge toxic chemical gases and volatile organic compounds into the atmosphere. Particulate material has also been removed from liquids by DAF floatation, another gravitational method, in which bubbles of a gas, such as air or oxygen, are introduced into the lower levels of the liquid and float to the top, carrying fine particles with them. These systems rely heavily on chemicals whereby chemical flocculates and microscopic air bubbles slowly float to the surface of a large flotation tank. This system is very costly and cumbersome requiring chemical mixers to blend flocculating chemicals such as alum (aluminum) with the raw influent before it enters a main tank. A large impeller pump injects high-pressure water containing excess dissolved air through an array of jet nozzles in the bottom of the tank. Mechanical scrapers push the float particles into a trough for removal and dewatering. These are relatively inefficient, in light of the outbreaks above-described, costly to operate and maintain, and require proper treatment and/or dispose of chemical residues and by-products.
Flotation is a gravitational method because the rise of bubbles is due to the gravitational acceleration acting on the mass of the liquid in accordance with the basic force equals mass time acceleration relationship. A force balance relative to a pocket of gas phase within liquid (a bubble), where the mass of the bubble is its volume times its density, shows that the bubble must rise to find equilibrium, because the density of a gas is generally less than that of a liquid. Large flotation tanks are required to allow adequate time for air bubbles to reach the surface.
Failure to remove all contaminants prior to filtration also leads to clogged filters, increases filter operation costs and wastes water required for frequent filter cleaning cycles. The use of flocculation promoting chemicals increases the volume of sludge to be dewatered and removed.
Thus, there is a continuing need for a pre-filtration (or pretreatment) separation system that will rapidly, efficiently, and effectively remove particles and volatile gases from liquids while treating a liquid, will efficiently remove algae and volatile gases (all contaminants) during pretreatment prior to filtration and will reduce overall treatment costs and conserves water through less frequent filter cleaning and a smaller sludge volume.
The present invention uses micro-bubbles with ionized ordinary ambient air (to form micro-bubbles) which basically blend with raw process water (raw influent). These micro-bubbles attach to suspended particles (contaminants) of the raw influent and are quickly removed from the water stream with a hydrocyclone vortex extraction column (separator). This extraction method is simple and environmentally friendly. No aluminum chemicals are used, which as a result reduces the volume of sludge to be disposed of in landfills. By simply removing most of the contaminants from the process water stream, the present invention prevents the formation of toxic chemical byproducts when necessary chlorine residuals are added to prevent bacterial regrowth in the community distribution system.
After removal of the contaminants, decontaminated water (which has been separated from the raw influent) is discharged to the filtration system and the waste water is discharged to a recovery system for recovery and removal of disposable and/or any recyclable waste (sludge) and re-processing of remaining waste water back through the system. This pre-filtration system was designed to remove contaminants from raw influent before it enters the treatment plant filtration system. It is simple, efficient, effective, low in maintenance, and environmentally friendly. No chemicals are used, which thereby reduces the volume of sludge to be disposed of in landfills. Removing most of the contaminants from the raw influent prevents the formation of toxic chemical disinfection byproducts, formed when chlorine chemical residuals are added to other systems to prevent bacterial re-growth in community water distribution systems.
Accordingly, several objects and advantages of my invention are to:
a. establish a pre-filtration system which is low in cost, easy to install, and easy to maintain;
b. provide a pre-filtration system which is relatively compact in size;
c. dramatically reduced replacement costs for a pre-filtration system;
d. provide for a pre-filtration system which is extremely efficient in separating waste matter, solids and gases, from an influent stream;
e. to minimize or eliminate the use of chemicals and toxins in a pre-filtration system; and
f. more safely and effectively pre-treat influent.
The foregoing has outlined some of the more pertinent objects of the present invention. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the intended invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner or by modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the summary of the invention and the detailed description of the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.
The above-noted problems, among others, are overcome by the present invention. Briefly stated, the present invention contemplates a pre-filtration water decontamination apparatus having an oxygen saturator for introducing high-pressure air and a high-pressure ozone-treated ionized water mixture therein and to substantially saturate this high-pressure treated/ionized water mixture with excess oxygen thereby creating a high-pressure oxygenated mixture (HPOM) stream; a blender for receiving and mixing the HPOM stream from the oxygen saturator with influent water containing contaminants to be removed; means for directing the HPOM stream from the oxygen saturator, at a pre-determined pressure, to the blender, and means for directing influent water to the blender at a lower pressure such that a white-water process (WWP) stream comprising a plurality of micro-bubbles is created in the blender; a separator for receiving the WWP stream from the blender and having means for causing upward vortex rotation of the WWP stream, for separating from the WWP stream a waste water stream along a central axis of the upward vortex of the separator, and for separating from the WWP stream a decontaminated water (DCW) stream along an outer wall of the separator; and a recovery unit for directing discharge of the DCW stream out of the apparatus through a water outlet, and for directing disposition of the waste water stream out of the apparatus for re-processing and for recycling.
The foregoing has outlined the more pertinent and important features of the present invention in order that the detailed description of the invention that follows may be better understood so the present contributions to the art may be more fully appreciated. Additional features of the present invention will be described hereinafter which form the subject of the claims. It should be appreciated by those skilled in the art that the conception and the disclosed specific embodiment may be readily utilized as a basis for modifying or designing other structures and methods for carrying out the same purposes of the present invention. It also should be realized by those skilled in the art that such equivalent constructions and methods do not depart from the spirit and scope of the inventions as set forth in the appended claims.